Blar i ICES CM documents authored by IMR scientists (1949-2011) på emneord "sonar"
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Abundance estimation of schools using a fisheries sonar
(ICES CM Documents;1991/B:35, Working paper, 1991)An attempt of abundance estimation of fish schooling close to surface using sonar was conducted in Eastern North Sea - Skagerrak in September 1990. The method is based on measurements of the school area by the Furuno ... -
An intership sonar calibration experiment in the Norwegian Sea
(ICES CM Documents;1996/B:22, Working paper, 1996)When migrating in the Norwegian Sea in spring and summertime, the Norwegian spring spawning herring will be surveyed by vessels from four nations. Because the herring may occur in schools close to the surface, use of ... -
Computerbased detection of schools for counting, quantification of size and swimming behavior by the SIMRAD SA950 sonar
(ICES CM Documents;1993/B:17, Working paper, 1993)As a help in stock assessment of pelagic, schooling fish a software for detection of schools and quantification of their size and swimming behaviour by a high resolution sonar has been developed. The system reads the ... -
Detection and counting of individual free-swimming krill using a 2MHz scanning sonar
(ICES CM Documents;1992/L:18, Working paper, 1992)The euphausiid crustacean Meganyctiphanes norvegica (M. Sars) have been detected and counted in the scanning section of a 2 MHz scanning sonar beam up to 3 meters from the sonar head. The tests completes a pilot investigation ... -
On the shape, size and density of North Sea herring schools as mapped by echo integration and accurate sonar projection
(ICES CM Documents;1993/B:16, Working paper, 1993)The shape and horizontal extent of herring schools in the North Sea have been mapped by a naval sonar (SIMRAD SA 950) with narrow horizontal beam width. The density of schools that were passed over was measured by the ... -
Preliminary results from tests using a high-frequency sonar as trawl-sonde
(ICES CM Documents;1986/B:37, Working paper, 1986)A high-frequency, short-range sonar is tested for trawl-geometry measurements on pelagic and bottom trawls. The sonar was operated on a standard, coaxial trawl sonde cable, and produced excellent images of the trawl ... -
Reactions of herring to trawling noise
(ICES CM Documents;1988/B:36, Working paper, 1988)The reaction of herring during pelagic trawl sampling has been studied by use of a high-frequency scanning sonar mounted on the headline of the trawl. The difficulties of obtaining high catch rates on shallow herring ... -
School geometry measurements using a sonar accuracy and an algorithm for school detection
(ICES CM Documents;1991/B:36, Working paper, 1991)The accuracy of geometric measurements of schools, using horizontal guided single-beam or multi-beam sonar, is simulated. For both types of sonars, the accuracy is dependent of horizontal beam-width and range. As multiple ... -
Sonar observations of schooling mackerel during purse seining
(ICES CM Documents;1988/B:27, Working paper, 1988)The swimming behaviour and horizontal dimensions of mackerel schools have been quantified by use of a multibeam, true motion sonar during purse seining in the Northern North Sea, August 1986. The horizontal dimensions ... -
A sonar study of the migration pattern of Norwegian spring-spawning herring (Clupea harengus L.) in July
(ICES CM documents, Working paper, 2000)About 700 schools of Norwegian spring-spawning herring (Clupea harengus L.) were tracked by multi-beam sonar during transect surveys in the Norwegian Sea in July 1995 and 1996. This herring stock usually concentrates in ... -
SONATE - Sonar effects on marine life - aiding naval officers in planning safe operation of active sonar
(ICES CM documents, Conference object, 2006) -
Trawl avoidance as a source of error in estimates of the prevalence of Icthyophonus hoferi disease in Norwegian spring spawning herring (Clupea harengus L.) in the feeding area
(ICES CM Documents;1995/H:8, Working paper, 1995)Summary: Results are presented from a survey in the Norwegian Sea in the summer 1993, where the abundance and distribution of herring was investigated, using a high resolution sonar and pelagic trawling at the surface. ...